1. Field of the Invention
This invention relates to water distribution systems, and more particularly, to water distribution systems powered by human power. The history of positive displacement reciprocating pumps goes back as far as 275 BC in Ancient Rome. In the sixteenth century, great lift and force pumps, driven by water wheels became the principle method for pumping water to be piped in Europe.
As late as 1987, the World Bank estimated that, throughout the world, 1.8 billion people would need improved water supplies, and that wells equipped with handpumps would be an appropriate choice to meet the needs of this number of people. Most of the reciprocating handpumps commonly used in developing countries have their origins in designs developed during the late 19th and early 20th Centuries in the United States and in Europe. In the United States, about 42 million handpumps were made until 1920, when electric pumps began to replace them. While the basic design of the reciprocating handpump has not changed much in this century, its typical use has changed greatly. In the early part of this century, in the United States and Europe, the big market for pumps was for small backyard pumps used for ten to thirty minutes per day by individual families or farmers. In a developing country today, a single pump may have to supply more than 500 villagers and may be in continuous operation for ten or more hours per day.
What is needed in a developing country is a manually operated pump which can be easily operated by a person for relatively long periods of time and which lifts significant volumes of water with as little effort as possible. Because of the high usage requirements, and because the pump must operate as a practical device far from cities having maintenance facilities and personnel, the pump must be both reliable and easily repaired. A handpump connected with a typical well is driven by pressing the end of a lever downward and by either pulling it upward, or permitting it to return upward due to the weight of the well. The work of lifting the water occurs as the lever is pressed downward. The simplest type of reciprocating pump is the suction pump, which draws water from shallow wells by creating a partial vacuum in a suction pipe. All of the moving parts, including a plunger moved by the lever and a suction check valve, are located above ground; only the suction pipe extends downward into the well. As the lever is pushed downward, the plunger is moved upward, lifting the water above it to be discharged through a spout, and pulling water below it upward through an open suction check valve. As the lever is moved upward, the plunger is moved downward, through the water below it, creating a pressure which opens a valve in the plunger while closing the suction check valve. Two disadvantages of this type of pump are first, it must be primed with water before it can be used and, second, the suction principle, depending on atmospheric pressure to lift water, limits the usefulness of the device to wells having depths less than about seven meters.
In deepwell reciprocating pumps, the cylinder is immersed within the well below the water level, being pulled up and down by a rod extending down the well pipe. This arrangement is suitable for wells as deep as 45 meters or more, with the operating limit depending on the effort that users are willing to apply for progressively less water at increased depths. As the depth of the well is increased, more work is required to lift the column of water in the well pipe, together with the steel rod extending down the well pipe to the cylinder.
One problem with most reciprocating pumps is caused by the fact that the lever used to operate the pump, while providing an exceedingly simple mechanism, does not make particularly good use of the ability of the human body to do mechanical work. The downward force that a person can provide to lift water in this way is limited by his own weight, and the lever primarily uses the muscles moving the arms and upper body, while, in a typical person, the muscles moving the leg are much stronger and more capable of use for extended times.
Another problem with most reciprocating pumps arises from the fact that the work of lifting the water and the pump mechanism occurs only as the lever is pushed down. For example, a conventional reciprocating pump requires a force of about 20 kg 3 as the lever is pushed down, while a force of only about 4 kg is required to move the lever back upward. Thus, uneven demands are placed on the user to supply energy to the pumping process.
A number of pump configurations have been built to overcome various of these disadvantages in the way driving forces are applied. For example, a treadle type foot pedal drive, together with a pair of flywheels, has been applied to a double piston pump, Model SB-115, produced by the Water Conservancy Bureau of Shandong Province, China. The Climax handpump, manufactured by Wildon Engineering of Worcester, United Kingdom, and the Volanta handpump, manufactured by Jensen Venneboer BV, The Netherlands, are both pumps in which a reciprocating motion is developed using a connecting rod driven by a rotating crank mounted on a shaft along with a flywheel. An eccentric rod extends from the flywheel for use as a hand crank. The Climax handpump also uses a counterweight to balance the lifting force applied through the crank.
Thus, the pump from Shandong Province, China, has the advantage of using the stronger muscles moving the legs, while the flywheels of all three of these types of pumps help to spread the force requirements over the operating cycles through the storage of energy. The counterweight of the Climax handpump provides additional help in evening torque requirements of the hand crank.
Nevertheless, the posture and leg movements of bicycle riding, which are known to be both comfortable and practical for providing mechanical work over an extended period, are not used for power input in these pumps. A bicycle type seating and pedaling arrangement is used to drive centrifugal pumps, Model 1-1/2-JB, produced by the Anyue County Farm Machinery Plant, Sichuan Province, China, and Model Jinshan-402B, produced by the Zhenjiang Sprinkler Plant, Jiangsu Province, China.
What is needed is a pump incorporating the posture and pedal configuration of a bicycle for power input with the simplicity, reliability, and flexibility of application of the reciprocating pump.
The force required to lift the water and rod mechanism of a reciprocating pump varies with the depth of the well. While the counterweight of the Climax pump attempts to balance this force, it cannot be moved to compensate for differences in well depth from one installation to another. Even within one installation, it is not unusual to increase the depth of a well to compensate for a falling water table. Therefore, what is needed is a way to vary the position of the counterweight to compensate for differences in force resulting primarily from differences in well depth.
The virtues of flywheels and of counterweighting are also discussed by S. Arlosoroff, et al., Community Water Supply The Handpump Option, (The World Bank, Washington, D.C., 1987) indicating that a properly counterbalanced flywheel in a pumping application can build up considerable speed, particularly when it is operated by two people. These editors further point out that counterweights should at least balance the pull of the pump rod and the plunger.
A conventional handpump or other reciprocating pump includes a spout extending outward and slightly downward from a point a few feet above the ground, below the point at which the pump is operated. Thus, at the spout, a rod extends upward through an opening, being attached to a lever or, in the case of the Climax and Volanta pumps, to a drive crank by means of a connecting rod. Since the top of the pump is not sealed, water cannot be raised above the spout by the pump. On the other hand, the electrically powered water pumping systems in developed countries are typically sealed in such a way that a substantial pressure can be developed above the pump. In a typical water system, this pressure is used either to raise the level of the water to an elevated storage level or to inject the water into a pressure tight tank at ground level. Water stored in this way is subsequently dispensed under pressure through a piping system, which may serve an individual rural house or an entire city.
In developing countries, this kind of water distribution is desirable too, although it is not generally achieved in rural areas. A piped system, supplying water for individual houses, provides significant advantages, both in terms of convenience and sanitation. Considering the changes described above in the patterns of usage of manually operated pumps, by which one pump may have to supply water for 500 villagers, what is particularly needed is a water supply system including a reciprocating pump which can be operated by means of a hand crank or pedal system and which can pump water under pressure into an elevated or pressurized tank.
2. Description of the Prior Art
U.S. Pat. No. 1,358,213 to Joerns describes a gear driven reciprocating pump having an upper seal, through which a pair of reciprocating rods operate, and a pressure chamber formed with a division wall and an outlet passageway, allowing the discharge of water near the top of the standard. This feature allows the pump to be operated under considerable pressure for various purposes, discharging a steady stream of water under the pressure of the pump.
While the pump of Joerns shows improvements in the mechanism used to produce reciprocating motion, the gear mechanism is still driven by a handle, or by an unspecified external source of power operating a pulley. What is needed, for the effective application of the Joerns device to the rural areas of a present day developing country, are the other components of a complete water system for supplying water to a number of faucets, together with means allowing the device to be operated by the more efficient process of pedaling.
U.S. Pat. No. 1,592,021 to De Lew et al and U.S. Pat. No. 4,886,430 to Veronesi et al. describe different types of pumping applications in which a flywheel is used. De Lew describes a detachable flywheel for use in a reciprocating oil well pump driven by an electric motor through a walking beam, while Veronesi describes the use of a flywheel, along with an electric motor and a centrifugal pump impeller, within a hermetically sealed casing, through which the fluid being pumped flows.
U.S. Pat. No. 5,016,870 to Bulloch et al describes an exercise device having a bicycle type pedal arrangement used to supply mechanical power to a flywheel, with an adjustable brake creating a variable resistance to the pedaling process.
It is thus an object of the present invention to provide a pedal and solar powered water pumpstand and water distribution system which includes clutch means for preventing forced pedal rotation injury to an operator.
It is another object of the present invention to provide such a pumpstand and water distribution system which includes clutch means for preventing forced rotation damage to a solar powered motor.
It is still another object of the present invention to provide such a pumpstand and water distribution system which includes a pressure tank having means for shutting off the release of water before all of the water is released, to maintain air pressure above the water.
It is a further object of the present invention to provide such a water distribution system which automatically switches pumpstand water flow from the pressure tank when the tank becomes full to another water retaining reservoir of any suitable type.
Still additional objects include providing a pump counterweight to balance the work done during the pumping stroke with work done during the downward stroke in the water pump and providing a counterweight which is radially adjustable to vary counter torque at different riser pump settings; providing flywheel store and release pedal energy at peak torque demand; providing a pressure chamber with a high pressure seal to guide and connect a connecting rod small end to pump rods, and a high pressure seal to allow pressure to build up to pump the water to a pressure tank or overhead reservoir; providing a water filtration system to filter sand and sediments; providing a water treatment system to feed necessary chemicals proportional to the flow and to preserve water when in storage; and providing an automatic control system which diverts pump discharge from a high pressure tank to an overhead reservoir and vice versa, an adjustable pilot valve mounted on the pressure tank which monitors the tank internal pressure, such that when pressure in the tank reaches a desired setting, the pilot valve feeds a signal to operate the sequence valve and divert the flow to the overhead tank, and such that a reverse process occurs when the pressure tank experiences a pressure drop, which further includes a pressure switch in the discharge pipe to the overhead tank, disconnects a solar power supply to the electric motor in the event the overhead tank becomes full, which further includes a pressure relief valve which prevents excessive system pressure due to clogging of the filter or accidental use of the wrong pressure setting on the pilot valve, and which finally includes a non-return check valve installed in the pipe line from the sequence valve to the pressure tank to prevent a reverse flow of water to the overhead tank when the position of the sequence valve is on overhead tank mode.